Highly-refractory article of tantalum and its alloys.



O. A. SIMPSON.

HIGHLY REFRACTORY ARTICLE OF TANTALUM AND ITS ALLOYS. APPLICATION man cm. 11, 1912.

- UTTO ARCHIBAIJD SIMPSON, F CHARLOTTENBURG, GERMANY, ASSIGNOR- TO SIEMENS & HALSKJE, A. Gr., OF BERLIN, GERMANY, A CORPORATION OF GERIWIANY.

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HIGHLY-REFRACTORY ARTICLE OF TAN'IALUM AND ITS ALLOYS.

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and residing at Charlottenburg, near Berlin, Germany, have invented a certain new and useful Improved Highly-Refractory Article of Tantalum and Its Alloys, of which the following is a specification.

My invention relates to articles of tantalum or an alloy of tantalum rendered highly refractory by a cover of platinum.

Since tantalum has been produced in a metallically pure form and very inexpensive processes of manufacturing the same have been devised, the'metal has become of great importance in the arts and has been widely used. This is owing to tantalum possessing a combination of excellent prop erties such as no other single metal "can be said to possess even approximately. Tantalum not only has a very high resistance to breaking strain, higher even than that of 7 iron, but, in addition, it is very elastic and can be very readily workedin the most various ways. For example, it can be drawn to form the finest wires. Also it can be hardened like the best steel. Further, tantalum has excellent chemical properties; at ordinary temperatures it is unaffected by the atmosphere and in this respect behaves like the noble metals. Likewise, at ordinary temperatures, it is not attacked by most acids. Its melting point is conslderably higher than that of platinum. Again, tantalum forms alloys. with other metals, tantalum-iron alloys being the best known, and the alloys can be subsequently welded with the metal employed to form the alloy. Another property of tantalum, and one which under some conditions is very important, is that it is almost or entirely nonmagnetic. Finally, in spite of all these valuable properties, it has the advantage of being cheaper than metals whose properties willbear any comparison at all with its own. Heretofore, however, tantalum has had one drawback, viz. that when it is exposedto the atmosphere, it begins to'oxidizen at temperatures of only a few hundred degrees centigrade. higher than 600 to 800 it may not be exposed to the air. Therefore, in spite of its extended use, a very large field of apworked up further .When it is at temperatures plication remains closed, namely it cannot be used whenever. high temperatures are involved. Very great endeavors have therefore been made to render tantalum usable in such cases also, but hitherto in vain.

primary object of my invention is to obvlate the above drawback, and to provide a new combination of metals which unites in itself all the above-mentioned desirable advantages and constitutes avery important addltlon to the arts. The production of such a metal has been successfully efiiected by-covering tantalum with platinum.

trative'feq nbodiment of my invention is shown 1 n perspective, whereina designate rod composed of tantalum Tn the accompanying drawing one illus- Specification of Letters Patent. Patented Apr. 25, ll ll fii. Application fiIed Uctober 17, 1912. Serial No. 726,257. i

pushed into an exactly fitting thin platinum tube 6. The new article of manufacture made in this manner may, if necessary, be as desired, by rolling or hammering. 1

It is, of course, well-known-to plate various metals with platinum. In every case,

however, this was done with the sole view of obtaining a cheap substitute for the expensive platinum. The problem in such cases was to find a new metal for certain purposes for which the known metals were largely or entirely unsuitable, for the one metal, platinum,'was available and combined in itself all the desired properties, but was much too costly. Tn bimetals of this kind known heretofore the properties of the starting or plated metal are not the determining factors. Also, in all cases one of the plated metals employed heretofore, e. g. copper, can be replaced'by another, 6. g. aluminium, without affecting those properties of the bimetal which are most important. According to my invention, however, I provide a new combination of metals for purposes for which no metalor combination of metals known heretofore could be employed,

a new combination of metals having properties such as are not even approximately closed to tantalum is open to my new com-- bination of metals. It can therefore be employed in all cases where use is made of high, and indeed the highest temperatures,

which on. y platinum could stand heretofore,

and such icases are of course exceedingly numerous'. I may mention, for example, the employment ofthe Wire composed of metals according to myfinvention for heating apparatus and for smelting-furnaces heated electrically by resistances; the employment of the combination of metals for making pins for artificial teeth, for making crucibles for very high temperatures, and so on; almost any desired number of examples could be given. Moreover, as the new combination ofmetals can be welded very well with platinum, copper and a number of other 15 metals, other fields of application, in which 'weldability is a necessity, are opened.

In addition, platinized tantalum is com- 1,1so,e14

'paratively inexpensive, because the plati- 1. Asa new article of manufacture,-a'

body comprising tantalum covered With platinum.

2. As a new article of manufacture, a body composed of an alloy of tantalum covered with platinum.

In testimony whereof, I have signed my name to this specification in the presence of two Witnesses.

OTTO ARCHIBALD SIMPSON.

Witnesses:

HENRY HASPER, WOLDEMAR HAUPT. 

